TWO INCOMING CMEs: A pair of solar eruptions on May 7th hurled coronal masss ejections (CMEs) toward Earth. Forecasttracks prepared by analysts at the Goddard Space Weather Lab suggests that clouds with arrive in succession on May 9th at 13:40 UT and May 10th at 07:54 UT (+/- 7 hours). The double impact could spark moderate geomagnetic storms. High-latitude sky watchers should be alert for auroras.

CORONAL HOLE: A dark hole in the sun's atmosphere (a 'coronal hole') is spewing a stream of solar wind toward Earth. The impact of the stream, expected on May 9-11, could add to the effect of the incoming CMEs, boosting the chances of strong geomagnetic activity later this week. NASA's Solar Dynamics Observatory took this picture of the opening on May 8th.

Coronal holes are places where the sun's global magnetic field opens up and allows some of the sun's atmosphere to escape. The outflow of gas is the solar wind. NOAA forecasters estimate a 40% chance of geomagnetic activity on May 9-10 when the stream arrives (along with the CMEs of May 7th). www.spaceweather.com